Catholic nuns hold placards as they protest against what organisers say are drug-related extrajudicial killings, during the International Human Rights Day in Manila, Philippines December 10, 2016. Photo: Reuters/Ezra Acayan

The United States has been a vocal critic of Philippine President Rodrigo Duterte's war on drugs, which has claimed more than 5,000 lives since he took office

The United States has not renewed a major aid package to the Philippines because of “significant concerns” about the rule of law under President Rodrigo Duterte, the US embassy said on Thursday.

“This decision reflects the Board’s significant concerns around rule of law and civil liberties in the Philippines,” embassy spokeswoman Molly Koscina said in a statement emailed to AFP after the country was not selected for a new Millennium Challenge Corporation grant.

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The previous five-year grant, which was worth US433.9 million, expired in May this year.

The US government set up the Millennium Challenge Corporation to promote economic growth and reduce poverty around the world.

However countries can only qualify if they “demonstrate a commitment to just and democratic governance, investments in its people, and economic freedom,” according to the corporation’s website.

The United States has been a vocal critic of Duterte’s war on drugs, which has claimed more than 5,000 lives since he took office nearly six months ago.

Duterte has insisted that police are only killing in self-defense

The criticism, including from President Barack Obama, has severely strained ties between the longtime allies.

Duterte has in response branded Obama a “son of a whore” and told him to “go to hell”, while seeking to establish closer ties with US rivals China and Russia.

Philippine police have reported killing 2,086 people in anti-drug operations since Duterte took office on June 30. More than 3,000 others have been killed in unexplained circumstances, according to official figures.

Often masked assailants break into shanty homes and kill people who have been tagged as drug traffickers or drug users. Rights groups have warned of a breakdown in the rule of law with police and hired assassins operating with complete impunity.

Duterte has insisted that police are only killing in self-defense and gangsters are murdering the other victims.

But he has also said he will not allow any police to go to jail if they are found guilty of murder in prosecuting his crime war.

This week Duterte said he had personally killed suspected criminals when he was mayor of a southern city to set an example for police.

In September Duterte likened himself to Nazi leader Adolf Hitler as he said he was “happy to slaughter” three million drug users.

After condemnation from Jewish groups, Duterte apologized for his Hitler reference but said he was “emphatic” about wanting to kill the millions of drug users.